The present invention relates to apparatus for driving automatic workpiece conveying devices in a press train. More particularly, the present invention relates to such conveying devices which include two standstill positions of the conveyor for facilitating pick up and delivery of the workpiece or articles being conveyed.
In prior art systems of this type, cam mechanisms have been employed substantially exclusively for the operation of such conveyors. Such prior art mechanisms, depending upon the purposes for which they are used, are equipped to operate as a single-cam drive or double-cam drive systems.
Disadvantages arise with such cam disk drive because of the limited power transmission available due to the linear or line contact between the cam disk and rollers cooperating therewith. Further problems arise with these cam disk drives with respect to adjusting the rollers with respect to the cam disks so as to assure contact therebetween. Also, the cam disks themselves are very expensive to manufacture due to the shapes required and the loads which they must withstand. Furthermore, the utilization of cam mechanisms in conjunction with frequently required stroke-increasing means (which stroke-increasing means usually consists of gears and racks) results in a considerably rough running of the machine using the cam disk drive conveyors.
The above-discussed disadvantages of the cam disk drive arrangements are avoided in a simple manner by the present invention. The present invention contemplates the utilization of an articulated drive, without the use of cams. Consequently, the drive of the present invention eliminates the need for the long so-called kingpin, which has heretofore been necessary in conventional cam mechanisms and which is very sensitive to twisting and/or must be of extremely thick dimensions. Such a kingpin has been required in the drive connection of the cam mechanism with the press drive. The use of an articulated drive connection in accordance with the present invention also provides for the possibility of the transmission of large forces while utilizing simple members for the construction of the driving interconnection between the press drive and the conveyor.
Also, with the arrangement of the present invention, stroke-increasing means are no longer necessary, since larger feeding steps can be obtained by articulated members configured as in the present invention, in a given space condition, than previously the case with cam drive mechanisms.
Another important feature of the present invention is the provision of an auxiliary drive mechanism for turning operations and the like, which auxiliary drive mechanism is interconnected with the articulated drive for the conveyor, in a particularly simple and useful manner.
In a preferred embodiment of auxiliary drive for turning operations, a two-armed lever with a guide means extending in the longitudinal direction thereof past the axis of rotation is connected for rotation with a rocking lever which forms part of the driving linkage for the conveyor. A slide block is displaceably arranged in this guide means and is provided with a pin to articulate a coupling rod thereto for driving a turning device.
An important advantage of this type of drive for a turning device resides in that the two positions wherein the motion of the conveyor comes to a standstill, resulting from the design of the articulated drive connection for the conveyor, can also be utilized for the pick up and delivery of the parts in the turning device. Furthermore, the adjustment of the slide block in the guide means to various spacings from the axis of rotation of the lever in its two arms makes it possible, on the one hand, to obtain differing swivel angles of the turning device, and on the other hand, to obtain selective pivoting of the turning device into respective opposite directions.
Preferably, the slide block has an internal thread engaged by an adjusting spindle rotatably supported in the lever. The mating of the internal thread and the thread of the adjusting spindle is preferably self-locking. Further, a motor is preferably attached to the lever, which motor is in driving connection with the adjusting spindle. With these arrangements, the variation of the slide block setting in the lever guide means may be facilitated also during operation of the apparatus.
For further background information on the environment with which the preferred embodiments of the present invention are particularly concerned, see U.S. Pat. Nos. 1,426,039; 2,352,632; 2,929,485; 3,105,399; 3,529,542; 3,499,334; and 3,707,908.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.